1. Field of the Invention
The present invention relates to a compact, high-variable power zoom lens and a variable power device, which are suitably used in a compact camera, an electronic still camera, and the like and, more particularly, to a compound zoom lens capable of changing a zooming range by adding an internal conversion lens along an optical path of a main lens, and a lens moving device for attaining the zooming operation.
2. Related Background Art
As a conventional photographing lens for a compact camera, a large number of zoom lenses each constituted by two lens groups, i.e., positive and negative lens groups have been proposed. For example, Japanese Laid-Open Patent Application No. 1-250917 proposed by the same applicant as the present invention is known.
A zoom lens constituted by four lens groups, i.e., positive, negative, positive, and negative lens groups is also known as a photographing lens for a compact camera, as disclosed in Japanese Laid-Open Patent Application No. 63-43115.
In the zoom lens constituted by the positive and negative lens groups disclosed in Japanese Laid-Open Patent Application No. 1-250917, however, a zoom lens in, e.g., the first embodiment of this patent application can have a compact structure since the total length at a wide-angle end is 53.35 mm. However, this zoom lens is not totally satisfactory since it has a zoom ratio of 2.19.
In Japanese Laid-Open Patent Application No. 63-43115, a high-variable power structure is attained by constituting the zoom lens by four lens groups, i.e., positive, negative, positive, and negative lens groups. For example, a zoom lens of the second embodiment disclosed in this patent application can have a zoom ratio as high as 2.76. However, in contrast to the former lens, the total length at a wide-angle end is 81.08 mm, resulting a large structure.